FIG. 7 shows a designing method for designing an electronic component, especially a flowchart using a CAD (computer-aided design) system. In starting the design of the electronic component, a predetermined electrical characteristic is determined in step 101. In step 102, electric constants of electrically equivalent circuits and the electronic components constituting them are determined by an electric circuit simulator or the like so that the electrical characteristic determined in step 101 satisfies a predetermined value. In step 103, physical shapes and conductive metal patterns of the electronic components or the like for achieving the electric constants determined in step 102 are determined.
Then, in step 104, based on the physical shapes of various electronic components determined in step 102, the electronic components or the like are laid out in a module, and wiring patterns between the electronic components and external terminals or the like are formed. In step 105, an electrical characteristic is measured, and it is determined whether or not the measured electrical characteristic matches with the predetermined electrical characteristic determined in step 101. When the predetermined electrical characteristic is not achieved, the process returns to step 103, and the processes of step 103 and later are repeated. When the predetermined electrical characteristic is achieved in step 105, all processes are completed.
In the conventional example, however, the designing efficiency is low. In the conventional configuration, the determination of the pattern shape of step 103 and layout design of step 104 have not yet been completed at the time of the electric circuit simulation of step 102, so that the electric circuit simulation considering the layout cannot be performed. Therefore, in the measurement stage of the electrical characteristic of step 105, frequently, the measured electrical characteristic does not match with the predetermined electrical characteristic. The simulation must therefore be repeated many times, and hence it is not easy to increase the designing efficiency. The electric circuit simulation of step 102 is performed by the electric circuit simulator, and the other steps are performed by a CAD system, so that the designing efficiency is not increased against expectations.
Conventional examples related to the present invention are disclosed in Japanese Patent Unexamined Publication No. 2003-16133 and Japanese Patent Unexamined Publication No. 2002-73718.